Matthew R. Abel, an attorney specializing in medical marijuana cases, meets in January 2012 with Brandy Zink and others leading the effort to legalize small amounts of marijuana. / Jessica J. Trevino, Detroit Free Press

by Bill Laitner, Detroit Free Press

by Bill Laitner, Detroit Free Press

Clarification: An earlier version of this story contained a quote that was misattributed.

The pros and cons of marijuana will take center stage Tuesday in Washington, D.C., when the Senate Judiciary Committee holds a landmark hearing on legalization.

Requested by committee Chairman Sen. Patrick Leahy, D-Vt., the hearing was triggered by U.S. Attorney General Eric Holder's announcement last month that federal authorities no longer will interfere as states adopt laws to allow medical marijuana or to legalize the drug entirely.

The hearing is on conflicts between state and federal marijuana laws. In calling for it, Leahy questioned whether, at a time of severe budget cutting, federal prosecutions of marijuana users are the best use of taxpayer dollars.

Dan Riffle, director of federal policies for the nonprofit lobby group Marijuana Policy Project in Washington, D.C., said he hopes for a breakthrough in the hearing that would lead to changes in federal banking laws, allowing marijuana sellers to accept credit cards and checks, not just cash.

That would do a lot to legitimize the nation's marijuana industry, safeguarding transactions from the risk of robberies and smoothing the route away from the black market and Mexico's drug cartels, Riffle said.

But "the elephant in the room is that we have an administration that's essentially working around federal law" to allow states to legalize marijuana, he said. "What we should do is just change federal law - just legalize marijuana."

This fall, Michigan lawmakers could take up bills that would ease laws on marijuana and widen medical users' access to it.

With public attitudes bending toward legalization in the last three years and reaching a majority in March, those who favor legal weed say they've reached a watershed year - one like 1930 might have felt to those who welcomed the nationwide legalization of alcohol in 1933.

Fans of legal marijuana say their cause just hit the tipping point, and point to a series of events that they say prove that legalization is on the cusp of being more than a pipe dream. They include that:

â?¢ In March, for the first time, a majority of Americans - 52% - told pollsters they favored legalizing marijuana, according to the Pew Research Center.

â?¢ In anticipation of retail pot stores opening this January, recreational users are reportedly flocking to Colorado and Washington state.

â?¢ Two national opinion leaders signaled changes of heart about cannabis. CNN medical correspondent Dr. Sanjay Gupta, in his documentary Weed last month, reversed the stance he expressed in his 2009 Time magazine article, "Why I Would Vote No on Pot." And U.S. Sen. John McCain, R-Ariz., told an audience in Tucson last week, "Maybe we should legalize marijuana. ... I respect the will of the people."

Planning to be in a front-row seat at Tuesday's hearing is Neill Franklin, who heads Law Enforcement Against Prohibition (LEAP), a nationwide group of mostly retired police, judges and corrections officers who want to see all street drugs legalized.

"A nationwide policy of prohibition leads to organized crime, underground crime, mass incarceration, very costly law enforcement, and ironically, the drugs become widely available and more dangerous because there are no quality-control standards," Franklin said last week.

"We saw that with alcohol," he said.

But not all at the hearing will be in favor of all-out legalization.

Kevin Sabet, a former senior adviser on drug policy to President Barack Obama's drug czar, is expected to testify that legalization is being rushed into the states without understanding its consequences.

His arguments are laid out in detail in his new book Reefer Sanity: Seven Great Myths about Marijuana, Sabet said.

"It's an appeal for a science-based and a health-based marijuana policy, not based on legalization but also not based on incarceration for small amounts" - and instead advocates wider access for marijuana users to state-of-the-art drug treatment programs, said Sabet, the director of the Drug Policy Institute at the University of Florida.

"Yes, there are medical properties in marijuana," Sabet said, "but we don't need to deliver that by smoking a joint or eating a brownie."